# Level of significance without mean given

• Nov 5th 2008, 08:11 PM
Alex103
Level of significance without mean given
Hi, i can't remember how to do this problem and i have been having trouble finding an answer.

The question is "An SRS of size 15 is taken from a normal distribution with standard deviation of 2. It is decided to test H0:u=20 versus H1=u<20. Whats the critical value at a 5% level of significance"

Also "the value of the test statistic for the sample is -1.62 then the p value for the test is ..."

I know the answers are -1.645 and 0.0526 respectivley. Can anyone help me out?
• Nov 8th 2008, 12:06 AM
mr fantastic
Quote:

Originally Posted by Alex103
Hi, i can't remember how to do this problem and i have been having trouble finding an answer.

The question is "An SRS of size 15 is taken from a normal distribution with standard deviation of 2. It is decided to test H0:u=20 versus H1=u<20. Whats the critical value at a 5% level of significance"

Mr F says: One sided test therefore the critical value is found from ${\color{red}\Pr(Z < z_{0.05}) = 0.05 \Rightarrow z_{0.05} = -1.645}$.

Also "the value of the test statistic for the sample is -1.62 then the p value for the test is ..."

Mr F says: p-value = Pr(Z < -1.62) = 0.0526.

I know the answers are -1.645 and 0.0526 respectivley. Can anyone help me out?

..
• Nov 8th 2008, 02:29 AM
Alex103
Hi, yeah i already figured it out but thanks anyway lol. My brain wasnt working that day.